this thread helped me figure out my similar issue (x1 set top box, sb8200 modem, two gocoaxes that kept having the moca light turn off, and a rogue 2.0 moca device showing up in link rates.) my theory that the STB or modem had moca and was interferring with gocoax. Switching on the secure communication option on all my gocoax seems to have stabilized my network.